3D Forward Modeling And Response Analysis Of The Controlled Source Electromagnetic Signal With IP Effect

Controlled-source audio-frequency magnetotellurics(CSAMT)and marine controlled-source electromagnetic(MCSEM)belong to controlled-source electromagnetic method which is significant methods of geophysical prospecting.The excitation source based on alternative electric field by artificial,produce induced polarization effect when medium was hypogeal polarization.In this paper,the three dimensional CSEM numerical simulation with the IP effect are focusing on the response characteristic.Based on basic principles of the Maxwell equation,the magnetic vector and a scalar potential under Lorenz gauge are derived with Cole-Cole model.Then using staggered grids and the finite volume method to discrete the potential equations based on the finite line source and implement the quasi-minimum-residual(QMR)iteration with jacobi to solve the large sparse and symmetrical liner equations system.Verified the accuracy of algorithm by comparison with one dimensional solution.As for homogeneous half space single low resistivity abnormity,analyzed the different polarization,time-domain frequency response correlation coefficients obtained results.The seawater depth,the charging rate,time constant,the response of the frequency correlation coefficient are analyzed by MCSEM three dimensional numerical simulation.The results provide the reference to three dimensional controlled source electromagnetic method inversion and anomaly interpretation.